We are studying the mechanical properties of carbon and substituted nanotubes. These nanometer scale structures have been shown to be the stiffest materials known in nature and to display remarkable flexibility and resistance to fracture. The nanoManipulator system was indispensable in our studies, which have appeared as a cover story in Nature (Oct. 10, 1997). Our current studies will broaden to include the mechanical properties of non-carbon nanotubes, as we have an in-house supply of silicon and metallic nanotubes as produced by a colleague, Otto Zhou, of the physics department. We are also very interested in the surface properties of nanotubes as model systems for nanometer-scale contact mechanics and friction. We have performed extensive manipulations of nanotubes and observed the canonical behavior of moving objects in contact: sliding, stick-slip and, finally, rolling. The latter is the first observation of this phenomena at the nanometer length scale. We are currently s tudying the substrate dependencies of these effects and attempting to observe the atomic-scale signatures of friction.